if i were to install a 3" magnaflow muffler on the stock exhaust system (i assume it's 2.75" kink bent like on lt1s). how much hp am i giving up not going with a 3" mandrel bent Ipipe? if i can fiind a shop that does 3" pipe i'll have them do the rest of it, but i was only able to cut the muffler and tips off my totalled car.

am i sacrificing that much power?

in the long run i plan to do MAC midlenghts w/o cats, put an QTP cutout on the Ypipe. i'm thinking i could save some $$ and not get a 3" I pipe...since i'll have the cutout for "just in case" races.

you guys have any input?

I kept the 2.75" when I installed my Magnaflow. I doubt the 3" would have added any additional hp. But if I could get 5hp or more from a 3 inch... I would do it.

Well, with all other things being equal, my cousin's car and mine are identical except for:

Him: Full Borla (3") Catback, 2.73

Me: !Muffler Stock Exhaust, 3.23

We have raced many a times, from a dig, from a roll, on the track, etc... and he is always a little faster than me (1-2 car lengths, or .1-.2 in the 1/4)

Granted, all cars are built differently, but the gear difference i thought would put me ahead.

Nope, its the I pipe, I told you! hehe j/k

Well I would not say that the Stock I-pipe is holding your car back but it could be that your cousins car is just putting out more power then your car. You can just take a look at different cars year for year and some cars will be putting more HP and Torque then cars of the same year. Also one question for you, have you changed the muffler on your car already ?? If you are still running the Stock Muffler, then that will tell you, that your cousins car will beat your car because the stock versus Borla, Stock muffler is too restrictive versus Magnaflow, Borla and Dynomax... But .25" Larger I-pipe is not going to make a lot more hp maybe 1 - 2 hp more... Personally I would not go a full cat back because stock I-pipe flows well enough for stock manifolds, heads and cam.. Now if you were to change the Heads and Cam then I would say go to either 3.5 " or 4 " I-pipe and different muffler..

I would say just save your money and buy a new muffler and tips(if you want different tips) and keep the stock I-pipe untill you do a Head and Cam swap (depending on what kind of heads and cam you buy..

Charlie

thanks guys...

i already have the magnaflow muffler and tips, which was all i was able to cut off the totalled car (was a complete cat back). in the near future i plan for MAC middies and i figure i'll put an electric cutout on the end of the Ypipe....so that will be there for those rare race moments...

My car already has no muffler and different tips. Its the equvilent of a loudmouth with the stock i-pipe

So all you are running is Straight Pipe then ?? Loudmouth does have a Resonator... My car does have a muffler since I do have the Dynomouth exhaust, which is basically like the LM except better sounding in my opinion... Then basically your cousins car must be putting out more power but the only way to prove it, would be to have both your cousin's car and your car dynoed ...

Charlie